Electrochemical batteries generally include pairs of oppositely charged plates (positive and negative), and an intervening electrolyte to convey ions from one plate to the other when the circuit through the battery is completed. The ability of the electrochemical battery to deliver electrical current is generally a straight-line function of the surface area of the plates which is contacted by the electrolyte. A flat plate constitutes a lower limit, which is frequently improved by sculpting the surface of the plate. For example, waffle shapes are known to have been used. However, there is a physical limitation to what can be done to “open-up” the surface of the plates, because the plates must resist substantial mechanical stringencies such as vibration and acceleration, and must be strongly supported at their edges. Thus, plates which are rendered delicate by casting or molding them into shapes which have thin sections are not a viable solution to increase the surface area of the plates. Further, such plates are subject to erosion and loss of material, thereby further reducing the strength of the plate over the life of the battery. A tempting solution is to use a woven screen for a plate. However, screens can be bent, usually on two axes. Especially after significant erosion they do not have sufficient structural strength. A battery is destroyed if a screen or plate collapses or contacts a neighboring screen/plate.
Despite the inherent potential structural disadvantages, it is a valid objective to attempt to increase the area exposed to the electrolyte by giving access to interior regions of a plate in order to increase the capacity and efficiency of the electrochemical battery. Otherwise the entire interior of the plate serves as no more than an electrical conductor and support for the surface of the plate. Holes through the plate can in fact increase surface area by the difference between their area removed from the surface and the added area of their walls. However, there is an obvious limitation to this approach.
A benefit in addition to increased surface area which could be obtained with an open-structured plate is the storage of electrolyte within the envelope of the plate. In turn, for a given amount of electrolyte volume, the gross volume of the battery can be reduced by the amount which is stored in the plates, rather than in the spacing between plates. Evidently the problem is one of increasing the surface area of the plates without compromising their strength.
Snaper, in U.S. Pat. No. 6,060,198 describes reticulated metal structures as plates for used as electrodes in the electrochemical battery. The reticulated structure consists of a plurality of pentagonally faced dodecahedrons. The reticulated metal structure is able to increase the capacity and efficiency of electrochemical batteries, while reducing the weight and unusable metals of the battery. However, the cost of making such metal forms may be cost prohibitive for commercial production. Further, depositing metals on the reticulated polymer substrate is difficult. Vacuum plating, plasma deposition and other methods may only deposit thick coats of metal on the bearing surface. Thus, the metal may not be able to penetrate deep into the core of the substrate, thereby limiting the reacting surface area within the core of the substrate.
Therefore, it would be desirable to provide a system and method that overcomes the above. The system and method would allow the surface area throughout the substrate to be uniformly coated with conductive material.